1. Field of the Invention
This invention relates to radiation monitors and more particularly to measuring instruments suitable for monitoring radiation of electric fields over a wide power range.
2. Description of the Prior Art
Diode detectors have been commonly used in radiation monitors to measure RF power or power density or field strength. An example of such is disclosed in U.S. Pat. No. 4,634,968 which issued on Jan. 6, 1987 to the inventor.
Such diode detectors exhibit a square law region. It is essential to operate the detector in the square law region for true RMS detection. True RMS operation is required to make accurate measurements when multiple signals, modulated signals and isotropic performance are involved.
A problem with convention diode detectors is that they exhibit a square law region only up to a maximum power of between about 20 and about 30 db. This limits the maximum power range over which the radiation monitor may operate.